Heat Quiz

A cupboard is placed in front of a heater. There is a small gap under the cupboard through which air can move. Which row best describes the temperature of the air in the gap and the direction of its movement?

1. Air temperature: Cool Air direction: Away from the heater
2. Air temperature: Cool Air direction: Towards the heater
3. Air temperature: Warm Air direction: Away from the heater
4. Air temperature: Warm Air direction: Towards the heater

Answer: (b) Air temperature: Cool Air direction: Towards the heater

Why is the line at Region D flat even though heat is continuously supplied?

1. Because temperature cannot rise beyond 100°C
2. Because energy changes liquid to vapour without raising temperature
3. Because molecules no longer vibrate
4. Because energy is being lost

Answer: (b) Because energy changes liquid to vapour without raising temperature

Match the phenomena with the type of heat transfer involved: Type of Heat Transfer Phenomena A Conduction 1 Land heating faster than sea B Convection 2 Metal spoon in hot soup C Radiation 3 Feeling warmth near a bonfire D Uneven heat capacity 4 Air circulating in a room heater

1. A- 1, B- 4, C- 3, D- 2
2. A- 2, B- 4, C- 3, D- 1
3. A- 1, B- 4, C- 3, D- 2
4. A- 2, B- 1, C- 3, D- 4

Answer: (b) A- 2, B- 4, C- 3, D- 1

Which part is labelled X and what is its function?

1. Capillary tube – transfers heat
2. Glass enclosure – for protection
3. Bulb – holds liquid for temperature expansion
4. Scale – shows temperature directly

Answer: (c) Bulb – holds liquid for temperature expansion

Choose the correct set of statements related to thermal expansion: 1. Bimetallic strips bend on heating due to different expansion rates 2. Expansion of solids is used in thermometer. 3. Railway tracks are laid with gaps to allow expansion 4. Liquids expand more than solids but less than gases

1. 1, 2, and 3
2. Only 1 and 2
3. Only 1 and 4
4. 1, 3 and 4

Answer: (d) 1, 3 and 4

Read the statement and choose the corect option: Assertion (A) : Radiators in heating systems are placed near the floor. Reason (R): Warm air rises and cold air sinks.

1. Both A and R are true, and R is the correct explanation
2. Both A and R are true, but R is not the correct explanation
3. A is true, but R is false
4. A is false, but R is true

Answer: (a) Both A and R are true, and R is the correct explanation

Which of these temperature conversions is correct?

1. 100°C = 212°F = 273 K
2. 0°C = 32°F = 0 K
3. –273°C = –459°F = 0 K
4. 0°C = –459°F = 273 K

Answer: (c) –273°C = –459°F = 0 K

Which of the following best explains why the woollen jacket is more effective in conserving body heat in such cold conditions?

1. Wool allows heat to move efficiently into the surrounding air
2. Wool reflects most of the external cold radiation away
3. Wool absorbs sweat rapidly and converts it to heat
4. Wool contains trapped air pockets that minimise heat loss by conduction and convection

Answer: (d) Wool contains trapped air pockets that minimise heat loss by conduction and convection

During a coastal science experiment, the wind direction sensor records wind moving from sea to land between 11:00 a.m. and 4:00 p.m. Which of the following conditions most likely changed after 4:00 p.m. to reverse this pattern?

1. Pressure over land increased due to cooling
2. Water heated up faster than land
3. Sunlight intensified causing strong convection
4. Air over the sea became lighter than air over land

Answer: (a) Pressure over land increased due to cooling

If the vacuum layer around X was accidentally filled with air, what would be the most likely outcome?

1. The flask would cool the liquid faster through conduction and convection
2. Heat transfer would reduce further
3. Liquid would stay at a constant pressure
4. Radiation loss would stop

Answer: (a) The flask would cool the liquid faster through conduction and convection